White dwarfs are weird objects. These dense cores of dead stars pack as much mass as the Sun into a body about the size of Earth. They’re left behind when a small- to mid-sized star ends its life by ballooning into a red giant and blowing off its outer layers in a series of explosive pulses. Although these puffs of ejected material eventually create a beautiful and expansive cloud of glowing gas called a planetary nebula, the process unfortunately tends to wreak havoc on any planets re